Portion of a keyboard



FIG. 1 is a perspective view of a portion of a keyboard showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a right side view thereof.

The contrast in shading techniques represents a contrast in appearance and does not represent any specific color, material or texture. The broken line immediately adjacent to the shaded area represents an unclaimed boundary of the design. The broken line showing of the remainder of the keyboard is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of a keyboard, as shown and described. 